Substrate processing method and apparatus

ABSTRACT

Provided are a substrate processing apparatus and a substrate processing method capable of achieving uniform trimming throughout an entire surface of a substrate. The substrate processing apparatus includes a gas channel including a center gas inlet and an additional gas inlet spaced apart from the center gas inlet, and a shower plate including a plurality of holes connected to the center gas inlet and the additional gas inlet, wherein a gas flow channel is formed having a clearance defined by a lower surface of the gas channel and an upper surface of the shower plate, the lower surface and the upper surface being substantially parallel.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2018-0020083, filed on Feb. 20, 2018 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND 1. Field

One or more embodiments relate to a substrate processing method and apparatus, and more particularly, to a substrate processing method and apparatus capable of improving characteristics of a thin film layer.

2. Description of the Related Art

In general, circuit line widths required in processes for manufacturing semiconductor devices are being reduced. In order to form circuit patterns having small widths, a technique of forming a thin film in an atomic layer unit is used along with a double-patterning technique or a quadruple-patterning technique. For example, U.S. Pat. Nos. 8,252,691, 8,901,016, and 9,171,716 disclose a spacer defined double patterning (SDDP) technique used to form a thin film on a mask through an atomic layer deposition (ALD) process, and application of a double-patterning technique by using the thin film as a spacer.

Also, U.S. Pat. No. 6,911,399, and U.S. Publication Nos. 2004/0018742, 2015/0079311, and 2015/0118846 disclose a trimming technique executed before forming a thin film on a pattern structure such as a mask. The above trimming technique is essential for precise controlling of critical dimensions (CD) of a circuit pattern, but has to be accompanied with an additional etching process for performing the trimming. Moreover, according to the trimming technique of the related art, the trimming may not be achieved evenly throughout the entire substrate, and accordingly, uniformity in the critical dimensions (CD) may not be guaranteed.

SUMMARY

One or more embodiments include a substrate processing method and apparatus.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more embodiments, a substrate processing method includes: applying plasma on a substrate including a pattern structure; trimming the pattern structure by independently supplying a first trimming gas and a second trimming gas, under a plasma atmosphere; and forming a thin film layer on a side surface and an upper surface of the pattern structure after the pattern structure is trimmed, wherein, during the trimming of the pattern structure, the first trimming gas is supplied through a center gas inlet of a gas supply unit, and the second trimming gas is supplied through an additional gas inlet that is spaced apart from the center gas inlet of the gas supply unit.

In the trimming of the pattern structure, a trimming amount of the pattern structure at a peripheral portion may be adjusted using the second trimming gas.

The forming of the thin film layer may include: supplying a source gas; and supplying a reaction gas, wherein at least one of the source gas and the reaction gas may be supplied through the center gas inlet and the additional gas inlet.

A thickness of a portion of the thin film layer located on a peripheral portion of the substrate may be adjusted by using at least one of the source gas and the reaction gas supplied through the additional gas inlet.

Each of the first trimming gas and the second trimming gas may include at least one of a diluted gas and an oxidant gas.

In the trimming of the pattern structure, a trimming amount of a peripheral portion of the pattern structure may depend upon at least one of elements including kinds, concentrations, and flow rates of the diluted gas or the oxidant gas.

In the trimming of the pattern structure, a trimming amount of a peripheral portion of the pattern structure may depend upon a flow rate ratio between the oxidant gas and the diluted gas.

A portion of the pattern structure at an edge portion of the substrate may be trimmed by an oxidant gas flowing through the additional gas inlet arranged around the center gas inlet.

A portion of the thin film layer on an edge portion of the substrate may be formed by a gas flowing through the additional gas inlet arranged around the center gas inlet.

The additional gas inlet may include a first additional gas inlet and a second additional gas inlet.

An oxidant gas is supplied through the first additional gas inlet and a diluted gas may be supplied through the second additional gas inlet.

According to one or more embodiments, a substrate processing method includes: applying plasma on a substrate on which a first pattern structure and a second pattern structure surrounding the first pattern structure are formed; trimming the first pattern structure and the second pattern structure by supplying a first trimming gas, under a plasma atmosphere; forming a thin film layer on the first and second pattern structures in-situ with the trimming of the first and second pattern structures; exposing upper surfaces of the first and second pattern structures by etching the thin film layer; and performing a patterning process by using the thin film layer as a mask, wherein, in the trimming of the first and second pattern structures, a trimming amount of the second pattern structure is controlled by independently supplying a second trimming gas in addition to the first trimming gas.

In the trimming of the first and second pattern structures, a ratio between a trimming amount of the second pattern structure and a trimming amount of the first pattern structure may be 0.5 to 1.5.

According to one or more embodiments, a substrate processing apparatus includes: a gas channel including a center gas inlet and an additional gas inlet that is spaced apart from the center gas inlet; and a shower plate including a plurality of holes connected to the center gas inlet and the additional gas inlet, wherein a gas flow channel is formed having a clearance defined by a lower surface of the gas channel and an upper surface of the shower plate, the lower surface and the upper surface being substantially parallel.

Processing of a substrate in a reaction may be locally controlled using an oxidant gas or a diluted gas supplied to the gas flow channel through the additional gas inlet.

The gas channel and the shower plate may face each other with respect to the clearance, and a surface of the shower plate facing the gas channel may have a conical shape.

The additional gas inlet may include at least two of a pair of a middle gas inlet and an edge gas inlet, wherein a pair of the middle gas inlet and the edge gas inlet and another pair of the middle gas inlet and the edge gas inlet may be symmetrically arranged with respect to the center gas inlet.

The at least two of the pair of the middle gas inlet and the edge gas inlet may be arranged to be spaced apart from each other by an angle of 180° or 120°.

The substrate processing apparatus may further include a sealing member between each pair of the middle gas inlet and the edge gas inlet.

An annular groove may be formed in a lower surface of the gas channel, and, at least one of the middle gas inlet and the edge gas inlet is linked with the gas flow channel via the annular groove.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure;

FIG. 2 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure;

FIG. 3 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure;

FIG. 4 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure;

FIG. 5 is a schematic cross-sectional view of a substrate processing apparatus according to an embodiment of the present disclosure;

FIGS. 6A, 6B and 7 are schematic diagrams for describing a substrate processing apparatus and a substrate processing method, according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram illustrating trimming processes performed by using a substrate processing apparatus, according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram illustrating processes of forming low-temperature atomic layer deposition (ALD)-SiO deposited in-situ after trimming, according to an embodiment of the present disclosure;

FIGS. 10 to 20 are cross-sectional views and plan views of substrate processing apparatuses according to embodiments of the present disclosure; and

FIGS. 21 to 27 are diagrams showing results of performing substrate processing methods by using substrate processing apparatuses according to embodiments of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

Hereinafter, one or more embodiments of the present disclosure will be described in detail with reference to accompanying drawings.

Embodiments of the present disclosure are offered to illustrate more fully aspects of the present disclosure to one of ordinary skill in the art and the following embodiments may be modified in the form of a range of the aspect of the present disclosure, but is not limited to the following embodiments. Rather, these embodiments are provided to further enhance the present disclosure, and to illustrate completely the aspect of the present disclosure to those skilled in the art.

The terms used in the present specification are merely used to describe particular embodiments, and are not intended to limit the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, regions, and/or sections, these elements, regions, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, region, or section from another region, layer, or section. Thus, a first element, region, or section discussed below could be termed a second element, region, or section without departing from the teachings of exemplary embodiments.

In the present disclosure, “gas” may include vaporized solid and/or liquid, and may include single gas or a mixture of gases. In the present disclosure, a processing gas introduced into a reaction chamber through a gas supply unit may include a precursor gas and an additive gas. The precursor gas and the additive gas may introduced into a reaction space typically as a mixture gas or separately. The precursor gas may be introduced with a carrier gas such as an inert gas. The additive gas may include a diluted gas such as a reactant gas and an inert gas. The reactant gas and the diluted gas may be introduced into the reaction space as a mixture or separately. The precursor may include two or more precursors, and the reactant gas may include two or reactant gases. The precursor is a gas that is chemisorped on a substrate and typically includes metalloid or metal elements configuring a main structure of a matrix in a dielectric layer, and the reactant gas for accumulation is a gas that reacts with the precursor that is chemisorped on the substrate when the gas is excited to fix an atomic layer or a monolayer on the substrate. “Chemisorption” denotes chemical saturated absorption. A gas other than the process gas, i.e., a gas introduced without passing through the gas supply unit, may be used for sealing the reaction space, which includes a seal gas such as an inert gas. In some embodiments, “film” refers to a layer continuously extending in a direction perpendicular to a thickness direction substantially without pinholes to cover an entire target or concerned surface, or simply a layer covering a target or concerned surface. In some embodiments, “layer” refers to a structure having a certain thickness formed on a surface or a synonym of film or a non-film structure. A film or layer may be constituted by a discrete single film or layer having certain characteristics or multiple films or layers, and a boundary between adjacent films or layers may or may not be clear and may be established based on physical, chemical, and/or any other characteristics, formation processes or sequence, and/or functions or purposes of the adjacent films or layers.

In the present disclosure, an expression “identical material” should be interpreted that main ingredients are identical. For example, when a first layer and a second layer are both silicon nitride layers formed of an identical material, the first layer may be selected from a group consisting of Si₂N, SiN, Si₃N₄, and Si₂N₃, and the second layer may be also selected from the above group, but detailed film quality of the second layer may be different from that of the first layer.

Additionally, in this disclosure, any two numbers of a variable may constitute a workable range of the variable as the workable range may be determined based on routine work, and any ranges indicated may include or exclude the endpoints. Additionally, any values of variables indicated (regardless of whether they are indicated with “about” or not) may refer to precise values or approximate values and include equivalents, and may refer to average, median, representative, majority, etc. in some embodiments.

In the present disclosure where conditions and/or structures are not specified, one of ordinary skill in the art may readily provide such conditions and/or structures, in view of the present disclosure, as a matter of routine experimentation. In all of the disclosed embodiments, any element used in an embodiment may be replaced with any elements equivalent thereto, including those explicitly, necessarily, or inherently disclosed herein, for the intended purposes. Further, the present disclosure may equally be applied to apparatuses and methods.

Hereinafter, the embodiments of the present invention will be described with reference to the drawings which schematically illustrate the embodiments. In the drawings, for example, depending on a manufacturing technology and/or tolerance, modifications of illustrated shapes may be expected. Accordingly, it should be understood that the embodiments of the present disclosure are not limited to particular shapes in areas shown in the specification and may include, for example, changes in shape caused during a manufacturing process.

FIG. 1 is a schematic flowchart for describing a substrate processing method according to an embodiment of the present disclosure.

Referring to FIG. 1, the substrate processing method may include applying plasma (first operation, S110), trimming a pattern structure (second operation, S120), and forming a thin film layer on the pattern structure (third operation, S130). Alternatively, the substrate processing method may further include forming a spacer from the thin film layer (fourth operation, S140), and patterning a substrate by using the spacer as a mask (fifth operation, S150).

First, the operation of applying plasma onto a substrate including a pattern structure (S110) is performed. The pattern structure recited herein denotes any type of structure formed on the substrate and having a certain pattern. For example, the pattern structure may be defined as a structure, in which a plurality of portions protruding from the substrate each has a side surface and an upper surface and are spaced apart from one another with a predetermined distance. The pattern structure may be a structure of a circuit in the structure, or a mask for forming the structure of the circuit (that is, for a post-patterning). The pattern structure may include a first pattern structure provided at a center of the substrate and a second pattern structure provided to surround the first pattern structure.

Alternatively, although not shown in the drawings, an operation of supplying an insert gas and/or an operation of adjusting pressure may be performed as a pre-process for sufficiently performing a trimming operation on a substrate in a reaction space. The operation of supplying the inert gas and/or the operation of adjusting pressure may be performed simultaneously with or before the operation of applying the plasma.

After that, under plasma atmosphere, an operation of trimming the pattern structure by independently supplying a first trimming gas and a second trimming gas to the reaction space is performed (S120). The first trimming gas and the second trimming gas may be supplied through different channels from each other, and kinds, concentrations, and flow rates of the first and second trimming gases may be independently adjusted from each other. Each of the first trimming gas and the second trimming gas may include at least one of a diluted gas and an oxidant gas. In an embodiment, an arbitrary material for trimming (etching) the pattern structure may be used as the first trimming gas and/or the second trimming gas.

O₂, NO, NO₂, N₂O, CO, CO₂, O₃, etc. may be used as the oxidant gas. N₂, Ar, He, H₂, Kr, Xe, Ne, etc. may be used as the diluted gas. However, a gas including fluoride (F) or chloride (Cl), other than the oxidant gas, may be used as the trimming gas described herein in order to etch the pattern structure.

During the trimming process, the first trimming gas may be supplied to the reaction space through a center gas inlet of a gas supply unit (S123), and the second trimming gas may be supplied to the reaction space through an additional gas inlet that is spaced apart from the center gas inlet of the gas supply unit (S125). The additional gas inlet may be located between a center and an edge of the gas supply unit, and accordingly, the additional gas inlet may affect a trimming amount of the pattern structure located on a peripheral portion.

For example, a gas flow channel may be formed between a gas channel and a gas unit including a shower plate. The first trimming gas may be supplied to the gas flow channel through the center gas inlet of the gas supply unit, and the second trimming gas may be supplied to the gas flow channel through the additional gas inlet of the gas supply unit. When the pattern structure includes the first pattern structure at a center portion (pattern structure located at the center of the substrate) and the second pattern structure surrounding the first pattern structure (pattern structure located at a peripheral portion of the substrate), a trimming amount of the second pattern structure may be controlled by controlling supply of the second trimming gas.

The trimming amount may be controlled by adjusting various elements during the processes. For example, by adjusting at least one of elements including a kind, concentration, and a flow rate of the trimming gas (that is, the diluted gas and/or oxidant gas) supplied to the additional gas inlet for being supplied to the peripheral portion of the substrate, the trimming amount of the pattern structure located at the peripheral portion may be adjusted. In additional embodiment, the trimming amount of the pattern structure located at the peripheral portion in the pattern structure may depend upon a flow rate ratio between the oxidant gas and the diluted gas.

In an embodiment, the additional gas inlet for supplying the second trimming gas may include a first additional gas inlet (middle gas inlet) and a second additional gas inlet (edge gas inlet). In an embodiment, the first additional gas inlet (middle gas inlet) may be arranged between the center gas inlet and the second additional gas inlet (edge gas inlet). For example, the oxidant gas may be supplied via the first additional gas inlet, and the diluted gas may be supplied via the second additional gas inlet. In another embodiment, the diluted gas may be supplied via the first additional gas inlet, and the oxidant gas may be supplied via the second additional gas inlet. In another embodiment, the first additional gas inlet and the second additional gas inlet may supply the same kind of gas (oxidant gas and/or diluted gas). Embodiments regarding this will be described below.

<Common Conditions among Embodiments>

A photoresist film pattern is formed on a wafer, and is trimmed at a susceptor temperature of 75° C. Oxygen is used as a trimming gas, and nitrogen is used as a diluted gas. As shown in FIG. 22, the wafer had a diameter of 300 mm, a center of the wafer was arranged at a starting point of an X-axis and a Y-axis and an alignment reference point was arranged at the Y-axis to perform a trimming operation, and after that, a trimming amount of the photoresist film pattern was measured in the X-axis direction.

<Example According to the Related Art (a Case there is no Additional Gas Inlet)>

Since the trimming gas only flows through the center gas inlet, the gas of high concentration flows on only one of a center and an edge of the shower plate. Moreover, since the oxidant gas and the diluted gas only flows in a chamber, it is difficult to locally control the trimming amount. Therefore, as shown in FIG. 23, the trimming amount of the photoresist film pattern on the wafer was not uniform throughout the X-axis of the wafer, and a bowl-shaped profile, in which a trimming amount at the center is greater or less than that at the edge, was observed.

Embodiment 1-1

A gas supply apparatus was designed to include a center gas inlet and an additional gas inlet, and the additional gas inlet includes a first additional gas inlet (middle gas inlet) and a second additional gas inlet (edge gas inlet) (see FIG. 12). A flow rate of O₂ gas supplied through the center gas inlet was set as 300 sccm. A flow rate of O₂ gas supplied through the middle gas inlet was set as 250 sccm, and a flow rate of Ar gas supplied through the edge gas inlet was set as 1450 sccm. A pressure in the chamber was 240 Pa, and HRF was set as 25 W. In this case, as shown in FIG. 24, a ratio between the trimming amount at the edge and the trimming amount at the center was 1.1 to 1.2, but a difference between the trimming amount at a left edge and the trimming amount at a right edge (about 0.5) was observed.

Embodiment 1-2

A gas supply apparatus was designed to include a center gas inlet and an additional gas inlet, and the additional gas inlet includes two pairs of first additional gas inlets (middle gas inlets) and a second additional gas inlet (edge gas inlet) (see FIG. 13). Also, the above two pairs were symmetrically arranged by an angle of 180. Except for the change in the gas supply apparatus, the photoresist film on the wafer was trimmed under the same condition as that of the embodiment 1-1. When comparing with the embodiment 1-1, as shown in FIG. 25, a ratio between the trimming amount at the edge and the trimming amount at the center was 1.1 and the trimming amounts at the left edge and the right edge were almost the same as each other.

Embodiment 2

The gas supply apparatus used in the embodiment 2 was the same as that used in the embodiment 1-2, and the embodiment 2 is different from the embodiment 1-2 in that O₂ gas was supplied through the center gas inlet, the middle gas inlet, and the edge gas inlet. Also, conditions on a flow rate of the gas were also changed in the embodiment 2, in addition to the kind of the gas. A flow rate of O₂ gas supplied through the center gas inlet was set as 1920 sccm, a flow rate of O₂ gas supplied through the middle gas inlet was set as 40 sccm, and a flow rate of O₂ gas supplied through the edge gas inlet was set as 40 sccm. In this case, as shown in FIG. 26, a ratio between the trimming amount at the edge and the trimming amount at the center was 1, that is, the trimming amounts were equal to each other (see Example 2 of FIG. 26). That is, under the conditions of the embodiment 2, the trimming was evenly achieved at the center and the edge of the wafer.

Embodiment 3

The embodiment 3 is different from the embodiment 2, in that O₂ gas was supplied through the center gas inlet and N₂ gas was supplied through the center gas inlet and the edge gas inlet. Also, conditions on a flow rate of the gas were also changed in the embodiment 3, in addition to the kind of the gas. A flow rate of O₂ gas supplied through the center gas inlet was set as 1700 sccm, a flow rate of N₂ gas supplied through the middle gas inlet was set as 100 sccm, and a flow rate of N₂ gas supplied through the edge gas inlet was set as 200 sccm. In this case, as shown in FIG. 26, a ratio between the trimming amount at the edge and the trimming amount at the center was 0.9, which denotes that the trimming was less made at the edge than the trimming at the center comparing with the previous embodiments (see Example 3 of FIG. 26).

As described above, since the additional second trimming gas is supplied independently from the first trimming gas, the uniform trimming on the pattern structure may be performed.

Although the embodiments of the present disclosure are described about the trimming of the pattern structure at the edge of the substrate by using the oxidant gas flowing through the additional gas inlet that is provided around the center gas inlet, the scope of the present disclosure is not limited thereto. The present disclosure relates to a technique of independently supplying the second trimming gas into an additional inlet after additionally forming the additional inlet at different location from a center inlet for supplying the first trimming gas, and as described above, the trimming may be evenly performed on the pattern structure by adjusting the kind and/or relative ratio (e.g., flow rate ratio) of the first and second trimming gases.

Referring back to FIG. 1, after performing the trimming, a thin film layer is formed on a side surface and an upper surface of the pattern structure (S130). Forming of the thin film layer may be performed through a deposition process, and the forming of the thin film layer may be performed in-situ with the above trimming operation (S120). In this case, an operation of purging a remaining gas may be performed between the trimming operation (S120) and the forming of the thin film layer (S130) (see S330 of FIG. 3).

For example, the forming of the thin film layer may be performed by using an atomic layer deposition process. In this case, the forming of the thin film layer may include a plurality of cycles that are repeatedly performed, wherein one cycle includes an operation of supplying a source gas and an operation of supplying a reaction gas. The operation of purging the remaining gas may be performed between the operation of supplying the source gas and the operation of supplying the reaction gas, and between cycles.

According to the embodiments of the present disclosure, at least one of the source gas and the reaction gas may be supplied through the center gas inlet, and additionally, may be also supplied through the additional gas inlet that is spaced apart from the center gas inlet. Therefore, a deposition thickness of the thin film layer located at the peripheral portion of the substrate may be adjusted by using at least one of the source gas and the reaction gas supplied through the additional gas inlet.

FIG. 2 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure. The substrate processing method according to the present embodiment may be a modified example of the substrate processing method according to the above-described embodiments. Hereinafter, descriptions about the same elements of the embodiments will be omitted.

Referring to FIG. 2, plasma is applied (S210), and the first trimming gas is supplied under a plasma atmosphere to trim the pattern structure on the substrate (S220). In more detail, the substrate may include the first pattern structure and the second pattern structure surrounding the first pattern structure. That is, in the pattern structure, the first pattern structure is arranged at a center of the substrate and the second pattern structure may be arranged on the peripheral portion of the substrate.

During the trimming process (S220), the first trimming gas may be supplied to trim the first pattern structure and the second pattern structure. The first trimming gas may be supplied, for example, through the center gas inlet that is arranged at a center of the gas supply unit (S223). The gas supply unit may be implemented as, for example, a shower head assembly, and in this case, the first trimming gas supplied through the center gas inlet may be distributed to flow towards the center and the periphery of the substrate. The distributed first trimming gas may trim the second pattern structure arranged on the periphery, as well as the first pattern structure at the center.

During the trimming process (S220), in addition to the first trimming gas, the second trimming gas may be independently supplied. The second trimming gas may be supplied, for example, through the additional gas inlet arranged around the gas supply unit (S225). Therefore, the trimming of the second pattern structure may not only be affected by the first trimming gas, but also affected by the second trimming gas.

As described above, the supplying condition of the second trimming gas is independently adjusted to control a trimming amount of the second pattern structure. For example, a flow rate of the oxidant gas is increased when supplying the second trimming gas through the additional gas inlet, and then, the trimming amount of the second pattern structure may be increased. On the other hand, a flow rate of the diluted gas is increased when supplying the second trimming gas through the additional gas inlet, and then, the trimming amount of the second pattern structure may be decreased. A ratio between the trimming amount of the second pattern structure and the trimming amount of the first pattern structure may be controlled by independently supplying the second trimming gas, and the above ratio may be, for example, from 0.5 to 1.5.

In one embodiment, the additional gas inlet may include a middle gas inlet and an edge gas inlet. The middle gas inlet may be arranged between the center gas inlet and the edge gas inlet. The oxidant gas and/or diluted gas may be supplied through the middle gas inlet, and may be supplied through the edge gas inlet (S228). The same kind of gases or different kinds of gases may be supplied through the middle gas inlet and the edge gas inlet.

After that, a post process is performed based on the trimmed pattern structure (S230). As an example of the post process, a thin film deposition process (in particular, the thin film process performed in-situ with the trimming process) may be performed. The thin film layer formed as above may become as a spacer through an etch-back process (a process of etching the thin film layer to only remain a spacer on a side wall of the pattern structure, and upper surfaces of the first pattern structure and the second pattern structure are exposed). After that, a patterning process may be performed by using the thin film layer that becomes a spacer as a mask.

During the thin film deposition process, a gas required in the deposition may be supplied to the reaction space through the center gas inlet and the additional gas inlet. Similarly to the trimming process, the thin film layer on an edge of the substrate (that is, thin film layer on the second pattern structure) may be generated by the gas flowing through the additional gas inlet that is arranged around the center gas inlet. That is, in addition to the supply of gas through the center gas inlet, by independently supplying the gas through the additional gas inlet, a ratio between a deposition amount at the center of the substrate and a deposition amount at the edge of the substrate may be controlled.

FIG. 3 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure. The substrate processing method according to the present embodiment may be a modified example of the substrate processing method according to the above-described embodiments. Hereinafter, descriptions about the same elements of the embodiments will be omitted.

Referring to FIG. 3, the substrate processing method includes a first operation for applying plasma (S310), a second operation for independently supplying the first trimming gas and the second trimming gas (S320), a third operation of purging the trimming gas (S330), a fourth operation of independently supplying a first source gas and a second source gas (S340), a fifth operation of purging the source gas (S350), a sixth operation of supplying a reaction gas (S360), and a seventh operation of purging a remaining gas (S370).

The first operation to the seventh operation S310 to S370 may be performed in the same chamber. Also, the fourth to seventh operations S340 to S370 are made as one cycle, and the cycle may be performed a plurality of times. In one embodiment, during the fourth operation to the seventh operation S340 to S370, a purge gas may be continuously supplied to the reaction space.

During the second operation S320, the first trimming gas may be supplied to the reaction space through the center gas inlet provided at the center of the gas supply unit. Also, the second trimming gas may be supplied to the reaction gas through the additional gas inlet provided between the center and the edge of the gas supply unit. By adjusting the component and the flow rate of the second trimming gas supplied through the additional gas inlet, uniformity of the trimmed pattern structure may vary.

Also, during the fourth operation S340, a first source gas is supplied to the reaction space through the center gas inlet provided at the center of the gas supply unit. Also, a second source gas may be supplied to the reaction space through the additional gas inlet provided between the center and the edge of the gas supply unit. By adjusting the component and the flow rate of the second source gas supplied through the additional gas inlet, uniformity of the thin film that is formed may be achieved.

FIG. 4 is a flowchart for describing a substrate processing method according to an embodiment of the present disclosure. The substrate processing method according to the present embodiment may be a modified example of the substrate processing method according to the above-described embodiments. Hereinafter, descriptions about the same elements of the embodiments will be omitted.

Referring to FIG. 4, the substrate processing method may include a first operation of applying plasma (S410), a second operation of independently supplying the first trimming gas and the second trimming gas (S420), a third operation of purging the trimming gas (S430), a fourth operation of supplying a source gas (S440), a fifth operation of purging the source gas (S450), a sixth operation of independently supplying a first reaction gas and a second reaction gas (S460), and a seventh operation of purging a remaining gas (S470).

During the second operation S420, the first trimming gas may be supplied to the reaction space through the center gas inlet provided at the center of the gas supply unit. Also, the second trimming gas may be supplied to the reaction space through the additional gas inlet provided between the center and the edge of the gas supply unit. By adjusting the component and the flow rate of the second trimming gas supplied through the additional gas inlet, uniformity of the trimmed pattern structure may be achieved.

Also, during the sixth operation S460, the first reaction gas is supplied to the reaction space through the center gas inlet provided at the center of the gas supply unit. Also, the second reaction gas may be supplied to the reaction space through the additional gas inlet provided between the center and the edge of the gas supply unit. By adjusting the component and the flow rate of the second reaction gas supplied through the additional gas inlet, uniformity of the thin film that is formed may be achieved.

In one embodiment, in order to further improve uniformity of the thin film, the first source gas may be supplied to the reaction space through the center gas inlet provided at the center of the gas supply unit and the second source gas may be supplied to the reaction space through the additional gas inlet provided between the center and the edge of the gas supply unit during the fourth operation S440.

FIG. 5 is a schematic cross-sectional view of a substrate processing apparatus according to an embodiment of the present disclosure. The substrate processing method according to the previous embodiments may be performed by using the substrate processing apparatus according to the embodiment. Hereinafter, descriptions about the same elements of the embodiments will be omitted.

Referring to FIG. 5, the substrate processing apparatus may include a barrier wall 510, a gas supply unit 520, an RF load 530, and an exhaust path 540. Examples of the substrate processing apparatus described herein may include a deposition apparatus of a semiconductor substrate or a display substrate, but the present disclosure is not limited thereto. The substrate processing apparatus may be any kind of apparatus that is necessary to perform deposition of a material for forming a thin film. In particular, it should be noted that the present disclosure is capable of in-situ performing a deposition process of a material for forming a thin film on a pattern structure and a trimming process of the pattern structure before the deposition in the same chamber.

The barrier wall 510 may be an element of a reactor. That is, a reaction space for processing the substrate (for example, trimming and/or deposition) may be formed by the barrier wall 510 structure. For example, the barrier wall 510 may include a side wall and/or an upper wall of the reactor. In the barrier wall 510, the upper wall portion of the reactor may provide a gas supply channel 550, and the first trimming gas, the second trimming gas, the source gas, the purge gas, and/or the reaction gas may be supplied through the gas supply channel 550.

The gas supply unit 520 may include a gas channel 525 and a shower plate 527. The gas channel 525 may include a center gas inlet at a center portion thereof. Also, the gas channel 520 may include additional gas inlets 585 and 587 that are spaced apart from the center gas inlet. The additional gas inlets 585 and 587 may include first and second additional gas inlets 585 and 587. The first additional gas inlet 585 may be arranged between the center gas inlet and the second additional gas inlet 587. The shower plate of the gas supply unit 520 may include a plurality of holes linked with the center gas inlet and the additional gas inlets 585 and 587, and accordingly, the gases supplied through the center gas inlet of the gas channel 520 may be distributed via the plurality of holes and supplied to the reaction space.

The gas supply unit 520 may be connected to the gas supply channel 550. In more detail, the center gas inlet provided in the gas channel 525 of the gas supply unit 520 may be connected to the gas supply channel 550. The gas supply unit 520 may be fixed to the reactor. For example, the gas supply unit 520 may be fixed on the barrier wall 510 via a fixing member (not shown). The gas supply unit 520 may be configured to supply a gas to a processing target in a reaction space 560. For example, the gas supply unit 520 may be a shower head assembly.

A gas flow channel 570 linked with the gas supply channel 550 may be formed in the gas supply unit 520. The gas flow channel 570 may be formed between the gas channel 525 (upper portion) of the gas supply unit 520 and the shower plate 527 (lower portion) of the gas supply unit 520. Although the gas channel 525 and the shower plate 527 are shown as separate structures from each other in the drawings, the gas channel 525 and the shower plate 527 may be integrally formed with each other.

In one exemplary embodiment, the gas flow channel 570 may extend having a constant width from the center towards the periphery of the gas supply unit 520. That is, a lower surface of the gas channel 525 may be parallel with an upper surface of the shower plate 527. Accordingly, the gas flow channel is formed having a clearance defined by the gas channel and the shower plate, wherein the gas channel and the shower plate are substantially in parallel. The gas channel 525 may provide a center inlet connected to the gas supply channel 550. The center inlet may be connected to the gas flow channel 570, and thus, the gas flow channel 570 may be connected to the gas supply channel 550 via the center inlet.

The gas channel and the shower plate may face each other with respect to the clearance therebetween. In one embodiment, a surface of the shower plate facing the gas channel may have a conical shape. Controllability during the trimming process may be improved through the above configuration, that is, the gas flow channel having the clearance substantially parallel between the gas channel (e.g., a lower surface thereof) and the shower plate (e.g., an upper surface thereof) and the structure of the shower plate having the conical shape and the gas channel facing the shower plate, and this will be described later.

The gas supply channel 550 may be formed in the barrier wall 510. In addition to the gas supply channel 550, a first through hole 580 may penetrate at least partially through the barrier wall 510. For example, the first through hole 580 may penetrate through the upper wall of the reactor, in the barrier wall 510. In some embodiments, the first through hole 580 may have a diameter that is smaller than that of the gas supply channel 550.

Also, a second through hole 582 may penetrate at least partially through the barrier wall 510. For example, the second through hole 582 may penetrate through the upper wall of the reactor, in the barrier wall 510. In some embodiments, the second through hole 582 may have a diameter that is smaller than that of the gas supply channel 550. The first through hole 580 may be arranged between the gas supply channel 550 and the second through hole 582.

The first additional gas inlet 585 may penetrate at least partially through the gas supply unit 520. For example, the first additional gas inlet 585 may penetrate through the gas channel 525 to be connected to the gas flow channel 570. Therefore, the first through hole 580 may be linked with the gas flow channel 570 via the first additional gas inlet 585.

Although a configuration in which the first through hole 580 is directly connected to the first additional gas inlet 585 in the drawings, the present disclosure is not limited thereto. The first through hole 580 provided in the barrier wall may be connected to the first additional gas inlet 585 via a connector (not shown), and the connector may be mounted on the gas supply unit 520.

The second additional gas inlet 587 may penetrate at least partially through the gas supply unit 520. For example, the second additional gas inlet 587 may penetrate through the gas channel 525 to be connected to the gas flow channel 570. Therefore, the second through hole 582 may be linked with the gas flow channel 570 via the second additional gas inlet 587. The first additional gas inlet 585 may be arranged between the gas supply channel 550 and the second additional gas inlet 587.

The first additional gas inlet 585 and the second additional gas inlet 587 may be arranged between the center and the edge of the gas flow channel 570. In particular, the first additional gas inlet 585 and the second additional gas inlet 587 may be spaced apart from the edge of the gas flow channel 570. Through the positional configuration of the first additional gas inlet 585 and the second additional gas inlet 587, trimming and thin film deposition on a certain portion of the substrate (that is, portions corresponding to the first additional gas inlet 585 and the second additional gas inlet 587) may be controlled.

For example, the trimming gas supplied through the first additional gas inlet 585 and the second additional gas inlet 587 may affect a trimming amount of the pattern structure arranged between the center and the edge of the substrate. When the trimming gas is an oxidant gas, a width of the pattern structure arranged between the center and the edge of the substrate may be greatly reduced (that is, may be trimmed greatly). When the supplied gas is a diluted gas, the width of the pattern structure arranged between the center and the edge of the substrate may be less reduced (that is, may be trimmed less).

Also, the gas supplied through the first additional gas inlet 585 and the second additional gas inlet 587 may affect uniformity of the thin film deposited on a portion between the center and the edge of the substrate. When the gas is a purge gas, a thickness of the thin film deposited on the portion between the center and the edge of the substrate may be reduced. When the gas is a reaction gas, the thickness of the thin film deposited on the portion between the center and the edge of the substrate may increase.

In the present specification, the first additional gas inlet 585 and the second additional gas inlet 587 may be respectively referred to as a middle gas inlet and the edge gas inlet. The middle gas inlet and the edge gas inlet may be arranged as a pair, and in particular, may be symmetrically arranged with respect to the center gas inlet. In other words, a pair of the middle gas inlet and the edge gas inlet and another pair of the middle gas inlet and the edge gas inlet may be symmetrically arranged with respect to the center gas inlet.

For example, two pairs of the middle gas inlets and the edge gas inlets may be arranged to be spaced by an angle of 180°. In another example, three pairs of middle gas inlets and the edge gas inlets may be arranged to be spaced by an angle of 120°.

In one embodiment, a sealing member may be formed between the first additional gas inlet 585 and the second additional gas inlet 587. Mixing of the gas supplied through the first additional gas inlet 585 and the gas supplied through the second additional gas inlet 587 may be prevented by the sealing member.

In another embodiment, an annular groove may be formed in a lower surface of the gas channel. The first additional gas inlet 585 and/or the second additional gas inlet 587 may be linked with the gas flow channel via the annular groove. Through the above configuration, the gas distribution in a circumferential direction may be uniform, and deviation in a trimming profile in a wafer may be improved. This will be described in detail later.

In another embodiment, a first buffer space 590 may be further provided between the first through hole 580 and the first additional gas inlet 585. The first buffer space 590 may temporarily store the gas supplied through the first through hole 580 to be evenly supplied to the first additional gas inlet 585. Therefore, a diameter or a width of the first buffer space 590 may be greater than a diameter or the width of the first through hole 580 and greater than a diameter or a width of the first additional gas inlet 585. Also, the first buffer space 590 may be successively formed along a circumference that is spaced a predetermined distance from a center of the gas supply channel 550.

Also, a second buffer space 592 may be further formed between the second through hole 582 and the second additional gas inlet 587. The second buffer space 592 may temporarily store the gas supplied through the second through hole 582 to be evenly supplied to the second additional gas inlet 587. Therefore, a diameter or a width of the second buffer space 592 may be greater than a diameter or the width of the second through hole 582 and greater than a diameter or a width of the second additional gas inlet 587. Also, the second buffer space 592 may be successively formed along a circumference that is spaced a predetermined distance from a center of the gas supply channel 550.

As described above, the present disclosure provides the gas supply unit 520 that evenly supplies the gas to the substrate, and in particular, the present disclosure provides a unit for improving the uniformity in the trimming and deposition of the thin film on the portion between the center and the edge of the substrate. Processes on the substrate in the reaction space may be locally controlled by the oxidant gas or the diluted gas supplied to the gas flow channel through the additional gas inlets 585 and 587.

The shower head structure generally adopts a structure, in which the reaction gas is supplied via the center portion and exhausted through the edge, but the trimming and deposition amount at the edge of the substrate and the trimming and deposition amount at the center of the substrate may not be even due to the above structure. However, according to the present disclosure, additional gas supplying paths are additionally provided to control the flow rate of the gas supplied to the portion between the center and the edge of the reaction space 560. The gas having the flow rate that is controlled as above may introduce a promoting effect or a blocking effect on the peripheral portion of the reaction space 560, and accordingly, the kind and amount of the gas supplied to the periphery of the substrate may be controlled.

FIGS. 6A, 6B, and 7 are schematic diagrams for describing a substrate processing apparatus and a substrate processing method according to an embodiment of the present disclosure. The substrate processing method and apparatus according to the present embodiment may be modified examples of the substrate processing method and apparatus according to the above-described embodiments. Hereinafter, descriptions about the same elements of the embodiments will be omitted.

As described above, the present disclosure is to precisely control the gas flow in the apparatus in order to locally control the trimming amount.

According to an embodiment, as shown in FIG. 6A, a photoresist (PR) layer is arranged on a substrate by using a spin coating process and processed (e.g., patterning) to a desired shape. After that, the substrate is transferred to an etching chamber, and a trimming is performed on the PR layer in the etching chamber. Then, the substrate is transferred to an additional deposition chamber for performing a deposition process, and a process of forming a SiO layer on the PR layer may be performed in the additional deposition chamber. After that, an etch-back process is performed on the SiO layer to separate the SiO layer on a side surface of the PR layer. The SiO layer separated above may be used as a mask in a post-process.

According to another embodiment, as shown in FIG. 6B, a PR layer is arranged on a substrate by using a spin coating process and processed to a desired shape. After that, the substrate is moved to a substrate processing apparatus (e.g., an atomic layer deposition (ALD) apparatus). After that, plasma trimming is performed by using a mixture gas of the oxidant gas and inert gas. When the PR layer is processed to the desired shape through the plasma trimming, the kind of gas is switched to continuously perform a process of forming a low-temperature ALD-SiO layer.

When the low-temperature ALD-SiO layer is formed after applying the resist layer (e.g., a photoresist layer), the resist layer may be processed to a predetermined thickness by an etching process, but an etching apparatus is necessary in addition to an apparatus for forming the ALD-SiO layer and manufacturing costs increase. In order to address this, according to the embodiments of the present disclosure, the resist layer is etched by the trimming process and formation of the ALD-SiO layer may be performed in-situ in the same chamber as shown in FIG. 6B, and accordingly, an additional etching device is not necessary and the manufacturing costs may be reduced.

The substrate processing apparatus (in particular, plasma ALD apparatus) capable of performing the trimming and film formation in-situ is shown in FIG. 7. A substrate 7 may be conveyed to a heat susceptor 5 that is set in advance to a temperature of 100° C. or less, for example, 75° C.

Next, an inert gas is transferred to a reaction chamber 3 via a gas introduction pipe 1 and a shower head 2. After that, a pressure in the reaction chamber 3 is set to be 50 to 12000 Pa, for example, 90 to 600 Pa, by a pressure adjustment valve 6.

In addition, radio frequency (RF) power 4 is applied between the heating susceptor 5 and the shower head 2 that are grounded for a predetermined time period, and the inert gas that becomes plasma is irradiated onto the substrate 7. Here, the applied RF power may be 0.12 W/cm² to 0.29 W/cm², for example, 0.12 W/cm² to 0.22 W/cm². After that, the applied RF power is adjusted to a desired RF power level. Here, the RF power is 0.028 W/cm² to 0.15 W/cm², for example, 0.028 W/cm² to 0.085 W/cm². After adjusting the RF power, the oxidant gas is introduced and plasma trimming is performed. After performing the plasma trimming, the kind of gas is switched and a low-temperature ALD-SiO₂ is continuously performed.

FIG. 8 simply expresses the series of trimming processes. That is, the pressure is adjusted and the inert gas is applied, the RF power of a first magnitude is applied, and then, the oxidant gas is introduced and the RF power is adjusted to a second magnitude that is smaller than the first magnitude.

FIG. 9 is a schematic diagram illustrating processes of forming low-temperature atomic layer deposition (ALD)-SiO deposited successively after trimming, according to an embodiment of the present disclosure. In a feed step, a precursor is introduced into the chamber, and precursor molecules are chemisorped on a surface of the substrate 7 on the heating susceptor 5. In a purge step, unnecessary precursor on the other portions than the surface of the substrate is removed, and distribution of the precursor molecules absorbed on the surface of the substrate is equalized. After that, in an RF ON step, the RF power 4 is applied between the heating susceptor 5 and the shower head 2 that are grounded for a predetermined time period, and the inert gas and the oxidant gas become plasma and are irradiated to the substrate to generate SiO₂ on the substrate 7. In a post-purge step, unnecessary gas generated during the film forming process is exhausted to prepare a next cycle.

FIGS. 10 to 20 are cross-sectional views and plan views of substrate processing apparatuses according to embodiments of the present disclosure. The substrate processing apparatuses according to the embodiments may be modified examples of the substrate processing apparatus according to the above-described embodiments. Hereinafter, descriptions about the same elements of the embodiments will be omitted.

Referring to FIG. 10, a gas supply unit 1000 is shown, and the gas supply unit includes a gas channel 1010 and a shower plate 1020, wherein the gas channel 1010 includes a plurality of gas flow paths including additional gas inlets (e.g., middle gas inlet and/or edge gas inlet) in addition to the center gas inlet. By employing the additional gas inlets, the gas may additionally flow around the edge (see FIG. 11) and around a space between the edge and the center (see FIG. 12), and accordingly, local controllability of the trimming amount may be improved.

For example, a trimming gas and/or a gas for forming a thin film may be supplied through a connector C provided on the gas supply unit 1000. In the above embodiment illustrated with reference to FIG. 5, the first through hole (580 of FIG. 5) connected to the additional gas inlet is provided in the barrier wall of the substrate processing apparatus, but according to the present embodiment, a first connection hole CH1 is provided in the connector C on the gas supply unit 1000. The connector C may transfer the gas supplied from outside to the additional gas inlet.

A first buffer space B1 may be formed between the first connection hole CH1 of the connector C and the additional gas inlet. A diameter or a width of the first buffer space B1 may be greater than a diameter or the width of the first connection hole CH1 and greater than a diameter or a width of the first additional gas inlet 585. Also, the first connection hole CH1 may include a first upper connection hole H3 and a first lower connection hole H1. In this case, a third buffer space B3 may be formed between the first upper connection hole H3 and the first lower connection hole H1.

Also, a second buffer space B2 may be formed between a second connection hole CH2 of the connector C and the additional gas inlet. A diameter or a width of the second buffer space B2 may be greater than a diameter or the width of the second connection hole CH2 and greater than a diameter or a width of the second additional gas inlet 587. Also, the second connection hole CH2 may include a first upper connection hole H4 and a first lower connection hole H2. In this case, a fourth buffer space B4 may be formed between the first upper connection hole H4 and the first lower connection hole H2.

In addition, in the embodiment illustrated in FIGS. 11 and 12, since the gas only flows on one point, a deviation is likely to occur in the profile of the trimming in the wafer, which may cause degradation in the device characteristics.

In this point of view, the present disclosure employs the structure in which the gas flows in two or more directions (FIGS. 13 and 14), and thus the structure precisely controls the flow rate of the gas flowing in two or more directions to correct the deviation in the profile of the wafer in the trimming apparatus.

As a method of precisely controlling the gas flow rate, a needle valve is used to adjust the flow rate of the gas flowing in two or more directions (or three or more directions) as shown in FIG. 15. Instead of the needle valve (or in addition to the needle valve), a mass flow controller or a splitter may be used. The substrate processing method according to an embodiment, by using the substrate processing apparatus of FIG. 15, will be described in detail below.

Embodiment 4

By using the substrate processing apparatus of FIG. 15, SiO₂ was deposited through the ALD cycle shown in FIG. 9 by using bisdiethylaminosilane that is a liquid material, oxygen, and argon gas, and results shown in FIG. 27 were obtained.

Here, when the profile of SiO₂ in the wafer is flat (see MZS4_Flat of FIG. 27), a temperature of the susceptor was set 75° C., the pressure in the chamber was 200 Pa, a flow rate of O₂ gas through the center gas inlet was 960 sccm, a flow rate of the Ar gas was 4000 sccm, and bisdiethylaminosilane also flowed in the supplying process. The O₂ gas through the middle gas inlet flowed at the flow rate of 20 sccm, and the O₂ gas through the edge gas inlet flowed at a flow rate of 20 sccm. In addition, HRF was set as 350 W.

When the profile in the wafer is in an edge high condition (see MZX4_Edge high of FIG. 27), a temperature of the susceptor was set 75° C., the pressure in the chamber was 200 Pa, a flow rate of O₂ gas through the center gas inlet was 120 sccm, a flow rate of the Ar gas was 4000 sccm, and bisdiethylaminosilane also flowed in the supplying process. The O₂ gas through the middle gas inlet flowed at the flow rate of4 sccm, and the O₂ gas through the edge gas inlet flowed at a flow rate of 1800 sccm. In addition, HRF was set as 350 W.

Also, when the profile in the wafer is in an edge low condition (see MZS4_Edge Low of FIG. 27), a temperature of the susceptor was set 75° C., the pressure in the chamber was 250 Pa, a flow rate of O₂ gas through the center gas inlet was 120 sccm, a flow rate of the Ar gas was 4000 sccm, and bisdiethylaminosilane also flowed in the supplying process. The Ar gas through the middle gas inlet flowed at the flow rate of 1800 sccm, and the Ar gas through the edge gas inlet flowed at a flow rate of 1800 sccm. In addition, HRF was set as 350 W.

As described above, the gases flow from locations facing each other with an angle of 180° , and thus, the flow rate of the gas may be precisely controlled, and a trimming amount on the wafer may be corrected and the wafer profile may be controlled. Also, during the ALD-SiO deposition, the wafer profile may be controlled.

Also, in addition to the precise control of the flow rate, in order to improve controllability in the wafer trimming profile, a sealing mechanism S may be introduced in order to prevent a mixture of the gases flowing from the edge and a mixture of the gases flowing between the edge and the center, as shown in FIG. 16. The sealing mechanism S may be arranged between the first connection hole CH1 and the second connection hole CH2.

Also, as shown in FIG. 17, the number of the holes may be changed in a portion represented as A in order to improve controllability of the trimming profile in the wafer. Also, as shown in FIG. 18, a size and/or a volume of the buffer space may be changed in a portion represented as B in order to improve controllability of the trimming.

In one embodiment, as shown in FIG. 19, the clearance between the gas channel and the shower plate is designed to have a narrow width and to be substantially parallel, and thus, the controllability of the trimming profile in the wafer may be greatly improved. Regarding to this, FIG. 21 shows a result of comparing the trimming result (see Parallel of FIG. 21) by using the substrate processing apparatus of FIG. 19 with a trimming result (see Non-Parallel of FIG. 21) by using the substrate processing apparatus, in which the width of the clearance between the gas channel and the shower plate is gradually reduced from the center portion to the peripheral portion. As shown in the trimming result of FIG. 21 (see Parallel of FIG. 21), in order to achieve uniformity of trimming, the gas flow channel may be formed to extend from the center towards the periphery of the gas supply unit and to have a constant width (i.e., a lower surface of the gas channel being parallel with an upper surface of the shower plate).

Also, as shown in FIG. 20, the annular groove is provided at a portion connected to the gas flow channel from the additional gas inlet at the edge and the additional gas inlet between the center and the edge, and thus, the gas may be evenly distributed in the circumferential direction and the deviation in the trimming profile in the wafer may be corrected.

For convenience of comprehension, the shapes of each element in the accompanying drawings are exemplary. In addition, the above shapes may be variously modified.

It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.

While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims. 

What is claimed is:
 1. A substrate processing apparatus comprising: a gas channel including a center gas inlet and a at least two additional gas inlets that are spaced apart from the center gas inlet; at least two through holes that are spaced apart from the center gas inlet and in fluid communication with the at least two additional gas inlets; at least two buffer spaces each comprising an outer wall, wherein a first buffer space is spaced apart from the center gas inlet and disposed above the gas channel and between a first through hole and a first additional gas inlet, and a second buffer space is spaced apart from the center gas inlet and disposed above the gas channel and between a second through hole and a second additional gas inlet; and a shower plate including a plurality of holes connected to the center gas inlet and the additional gas inlet, wherein a gas flow channel is formed having a volume defined by a surface of the gas channel and a surface of the shower plate, the surface of the gas channel and the surface of the shower plate being substantially parallel, wherein the at least two additional gas inlets begins at an upper surface of the gas channel and terminates at a lower surface of the gas channel, wherein the center gas inlet begins above the gas channel and terminates at the lower surface of the gas channel, wherein the first buffer space begins at a lower end of the first through hole and terminates at the upper surface of the gas channel, wherein the second buffer space begins at a lower end of the second through hole and terminates at the upper surface of the gas channel, wherein the at least two buffer spaces have a greater width than a width of one of the at least two through hole and a width of one of the at least two additional gas inlet, and wherein a first gas flow path through the first through hole terminates at the gas flow channel, wherein the first gas flow path between the first through hole and the gas flow channel consists of a path through the first buffer space and the first additional gas inlet, wherein a second gas flow path through the second through hole terminates at the gas flow channel, wherein the second gas flow path between the second through hole and the gas flow channel consists of a path through the second buffer space and the second additional gas inlet, wherein a third gas flow path through the center gas inlet terminates at the gas flow channel, and wherein the first gas flow path is isolated from the third gas flow path.
 2. The substrate processing apparatus of claim 1, wherein the at least two additional gas inlets are configured to supply an oxidant gas or a diluted gas to the gas flow channel.
 3. The substrate processing apparatus of claim 1, wherein the gas channel and the shower plate face each other with respect to the clearance, and a surface of the shower plate facing the gas channel has a conical shape.
 4. The substrate processing apparatus of claim 1, wherein the at least two additional gas inlets includes at least two of a pair of an middle gas inlet and an edge gas inlet, wherein a pair of the middle gas inlet and the edge gas inlet and another pair of the middle gas inlet and the edge gas inlet are symmetrically arranged with respect to the center gas inlet.
 5. The substrate processing apparatus of claim 4, wherein the at least two of the pair of the middle gas inlet and the edge gas inlet are arranged to be spaced apart from each other by an angle of 120°.
 6. The substrate processing apparatus of claim 4, further comprising a sealing member between each pair of the middle gas inlet and the edge gas inlet.
 7. The substrate processing apparatus of claim 4, wherein an annular groove is formed in a lower surface of the gas channel, and at least one of the middle gas inlet and the edge gas inlet is linked with the gas flow channel via the annular groove.
 8. The substrate processing apparatus of claim 1, wherein the at least two additional gas inlets have a different diameter than the diameter of the center gas inlet.
 9. The substrate processing apparatus of claim 1, wherein the first gas flow path is defined by a path consisting of the first through hole, the first buffer space, and the first additional gas inlet.
 10. The substrate processing apparatus of claim 1, wherein the at least two buffer spaces are formed within a wall adjacent the gas channel.
 11. The substrate processing apparatus of claim 1, wherein a first gas flow flows through the first gas flow path, wherein a second gas flows through the third gas flow path, and wherein the first gas and the second gas are different.
 12. The substrate processing apparatus of claim 1, wherein the gas channel comprises an outer portion and an inner portion, wherein the shower plate comprises an outer portion and an inner portion, and wherein the outer portion of the gas channel contacts the outer portion of the shower plate.
 13. The substrate processing apparatus of claim 1, wherein the diameter of the center gas inlet is greater than a width of one of the at least two buffer spaces. 